This application is to request funds ($291,170) to purchase the instruments, related accessories, computer, and software necessary to build a complete system for the production and analysis of spotted DNA microarrays. These are the Packard Biochip Technologies BioChip Arrayer, the ScanArray 4000 scanner, and the Packard Mutiprobe II robotic sample handling system. The microarray facility will be housed at the University of South Carolina School of Medicine, as an integral part of the well-established shared Instrumentation Resource Facility (IRF). The IRF is a core research and teaching facility used by more than 100 faculty, staff and students from the USC School of Medicine, the affiliated Dorn VA and Palmetto Richland Memorial Hospital, as well as by members of the South Carolina Cancer Center. The microarray faculity will serve 11 major users, most of whom are recipients of NIH grants. Many more investigators have expressed an interest in the technology, and a list of minor users already includes six investigators, and it is growing. Virtually all users are currently funded by external, peer reviewed sources, including the American Cancer Society, the American Heart Association, the Department of Defense, etc The microarray facility will serve all University of South Carolina faculty, students and staff researchers who have a need for this state-of-the-art technology. In addition, as it is the case with all IRF resources, the facility will be available to all interested researchers at MUSC, Clemson University, and other state and regional institutions. While there are two Affymetrics gene-chip facilities at a relative close distance (about 100 miles from USC: one at MUSC and the other at the Medical College of Georgia) there are currently no spotted array facilities available in this area. The development of DNA arrays, and more recently of microarrays represents a milestone of molecular biology, probably comparable in impact to the invention of PCR. Coupled with the complete sequencing of the human genome and of those of other species, this technology is taking studies of gene expression and DNA polymorphism to an entirely different level. Alterations in gene expression patterns or DNA polymorphisms determine or profoundly influence all biological functions. Variations in gene expression are at the core of development, differentiation, normal cell physiology, and alterations of gene expression drive or influence virtually all pathologic processes. DNA array technologies provide rapid and cost-effective means of identifying gene expression and genetic variations. Ready access to this technology is badly needed at the University of South Carolina and will foster tremendous growth in the biomedical research programs of this University and neighboring institutions.